With a continuously growing population, it is becoming increasingly difficult to meet the world's energy needs and, simultaneously, to control carbon emissions to kerb greenhouse gas emissions which are considered responsible for global warming phenomena. These concerns have triggered a drive towards a more efficient use of electricity in an attempt to reduce energy consumption.
One such area of concern is lighting applications, either in domestic or commercial settings. There is a clear trend towards the replacement of traditional, relatively energy-inefficient, light bulbs such as incandescent or fluorescent light bulbs with more energy efficient replacements. Indeed, in many jurisdictions the production and retailing of incandescent light bulbs has been outlawed, thus forcing consumers to buy energy-efficient alternatives, e.g. when replacing incandescent light bulbs.
A particularly promising alternative is provided by solid state lighting (SSL) devices, which can produce a corresponding luminous output at a fraction of the energy cost of incandescent or fluorescent light bulbs. An example of such a SSL element is a light emitting diode (LED).
It is known to provide SSL lighting devices having a similar overall shape to fluorescent light tubes, i.e. tubular solid state lighting devices. Such devices can provide a form factor that is comparable with traditional lighting devices, this can aid market penetration as customers may like or be accustomed to the form factors of such fluorescent light tubes. These tubular SSL devices may be used to replace fluorescent light tubes or used in similar applications to fluorescent light tubes. In particular, these SSL lighting devices may be particularly easy to retro-fit in place of fluorescent light tubes.
An example of a prior art tubular SSL element-based lighting device comprises a tubular housing, within the tubular housing is a printed circuit board onto which a plurality of LED elements are mounted at regular intervals. In this known low-cost construction, the printed circuit board (PCB) is directly attached to the tubular housing using adhesive. However, this results in a very wide beam angle, which can be undesired. It is also known to provide a metal reflector for beam shaping between the PCB and the tubular body, however, the cost of this reflector may be high and the complexity of assembly of the lighting device is increased, which results in an overall more expensive device.